Sunscreen: the Basics
by Diana Clarke
Ah, those rainy days and dark gloomy nights are almost behind us. It's time to start planning days at the seaside, picnics in the park and hikes along the creek and through the meadow. But when you plan your outing, consider this:
Dermatologists believe most people
don't know the basics of sunscreen use and are therefore at a higher risk of developing not only skin damage and wrinkles, but also skin cancer.
“The most important thing to know about sunscreen is that, regardless of skin type and ethnicity, everyone needs to use it,” advised dermatologist Zoe Diana Draelos, M.D., a clinical associate professor in the Department of Dermatology at Wake Forest University in Winston-Salem, N.C.
“If a person is going to be in the sun for more than 20 minutes, the American Academy of Dermatology recommends using a broad-spectrum sunscreen with a Sun Protection Factor (SPF) of at least 15 for basic protection year-round.”
Sunscreens absorb, reflect or scatter Ultraviolet (UV) on the skin. But some UV rays still penetrate the skin. Therefore, sunscreens should be used to avoid sunburn, not to stay in the sun longer.
Sunscreen Type and Use
Sunscreen should be water resistent whether it is in the form of a creams, gels, lotion or wax stick. Otherwise, the sunscreen will come off easily during swimming or sweating. In addition, sunscreen should be used on cloudy days because 80 % of damaging solar rays can still pass through clouds.
Suscreen Ingredients
Dr. Draelos advised using sunscreens with broad-spectrum ( UVA and UVB) sun protection. Ingredients include benzophenones (oxybenzone), cinnamates (octylmethyl cinnamate and cinoxate), sulisobenzone, salicylates, titanium dioxide, zinc oxide, and avobenzone (Parsol 1789).
Sun Protection Factor
All sunscreens are labeled with Sun Protection Factor (SPF) numbers. The higher the number, the greater the protection. The sunscreen SPF rating is calculated by how long a sunburn would take to appear on sun protected skin compared with unprotected skin.
For example, If your skin normally take 5 minutes to burn, a sunscreen with a SPF of 15 would allow you to stay in the sun 15 times longer before showing signs of burning. Also, A suncreen with a SPF of 15 has 93 percent absorption of UV rays whereby a SPF of 30 has 97 percent absorption.
The SPF number on sunscreens signify screening ability for only UVB rays. Currently, the FDA does not have a rating system for UVA protection.
“Since an SPF measurement is the most protection a person can receive under the best possible conditions, many times sunscreens do not perform up to labeled SPF ratings,” commented Dr. Draelos. “This is due to a variety of factors, including the effects of wind, humidity, perspiration and facial movement, as well as uneven product application. Many people also wait too long to reapply.”
Sunscreen Application
Follow these simple guidelines:
- Apply to dry skin 15-30 minutes before going outdoors.
- Reapply sunscreen every two hours.
- Use about one ounce to cover the exposed areas of the body correctly.
- Apply lip balm that contains sunscreen with SPF 15 or higher.
Comprehensive Sun Protection Regimen
“Sunscreen technology is constantly evolving,” stated Dr. Draelos. “New technology has the potential to reduce movement of sunscreen on the skin after application and enhance its ability to deflect the sun’s rays. However, sunscreens are only one part of a comprehensive sun protection regimen and should be used in conjunction with other protective methods.”
Besides wearing sunscreen, the AAD recommends the following sun protection practices:
- avoid sun exposure between 10 a.m. and 4 p.m. when UV rays are most intense
- seek shade
- wear wide-brimmed hats, sunglasses and clothing with a tight weave.
- avoid the sun when you're shadow is shorter than you. When your shadow is short, UV rays are strong.
- don't use tanning beds.
Source: American Academy of Dermatology
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Last modified: 04/27/05
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